1. Field of Invention.
This invention relates to an automatic balancing type pen recorder having a servomechanism.
2. Discussion of the Prior Art.
Pen recorders are known and are used in analog recording of various measurement signals. For example, FIG. 1 shows a conventional automatic balancing type pen recorder, wherein a chart cassette 1 houses a recording chart 2 and is adapted to be detachably mounted on a main body chasis(not shown) . A pen carriage 3, upon which is detachably mounted a pen 4, is slidably fit over a guide shaft 5 extending in a direction perpendicular to the direction of feed of chart 2. A driving system 6 causes reciprocal movement of pen carriage 3 along its guide shaft 5 which is driven by a servomotor 7. A potentiometer 8 feeds back the position of the pen carriage 3. Servomotor 7 and potentiometer 8 constitute a servo unit which is connected through lead wires 9,10 and connectors 11,12 to a base circuit board 13 which in turn is connected to a servo amplifier board 14 and a preamplifier board 15.
Conventional pen recorders of this type use a plurality of lead wires and connectors. Thus, it is difficult to obtain high packing density. Also, such conventional pen recorders are prone to failure due to unsatisfactory connections and disconnections.
Furthermore, in order to manufacture a recorder utilizing a plurality of pens (so called multi-pen recorder), each pen recording system therein must be provided with a separate servo unit of the type shown in FIG. 1. Thus, considerably large installation space is required, and accordingly a compact size multi-pen recorder is difficult to obtain.
Moreover, a conventional pen recorder is not provided with mechanism for printing predetermined print patterns, such as feed rate of the recorder chart, date of measurement, time of measurement, alarm information, time marker, etc, which are usually associated with the recording of measurement signals. Thus, the described recorder cannot conveniently analyze recorded data.
In addition, the conventional recorder reads out the measurement signal from the position of the pen carriage and records same on the chart. Thus, it is difficult to obtain a complete picture of the measured data. This defect is pronounced especially in a multi-pen recorder, wherein measurement results are recorded on the chart by correcting or adjusting time differences corresponding to the distances between adjacent pens disposed in the direction of feed of the chart.